PHOENIX -- A couple of days after breathing new life into the conspiracy theory that Barack Obama is not eligible to be president, the chairman of the Arizona Republican Party says he's not running for another term.

The announcement is a surprise as Tom Morrissey had publicly said he would seek a second two-year term during the GOP's annual organizational meeting next month.

Morrissey said Wednesday it was a tough decision but he is stepping down because of health reasons. On Monday, Morrissey and a pair of other Republicans questioned the authenticity of Obama's certificate, rekindling a long debunked theory.

The comments made national headlines because it happened during the state's Electoral College meeting, as presidential electors here and across the nation officially elected Obama over Mitt Romney.

Although the president has shown documentation that he was born in Hawaii and is therefore eligible to serve as commander-in-chief, Morrissy said he wasn't satisfied with what he's seen.

"I think for somebody in the president's position to not have produced a document that looks more legitimate, I have a problem with that," said Morrissey.

Also jumping on the "birther" bandwagon Monday was former Gila County Republican Party Chairman Don Ascoli and John Rhodes, according to the Associated Press.

The idea that Obama did not meet the constitutional requirement that presidents be born in the United States first gained traction four years ago during his first national campaign. But since then, Arizona has become ground zero for "birtherism."

The state legislature has introduced legislation that would have potentially kept Obama off the ballot, Maricopa County Sheriff Joe Arpaio launched an investigation into the president's birth certificate and most recently Secretary of State Ken Bennett looked into the issue.

Calls for the president to show more documentation had died down in May after Bennett said he got a copy of Obama birth certificate. But Morrissey stoked the fires again during what is normally an uneventful meeting.

When asked why he wasn't going to run again, Morrissey said he was preparing to undergo surgery for a knee replacement. He said he needed some peace and quiet after the medical procedure.

"During a recovery you want your stress level to be as low as possible and this job is loaded with stress," Morrissey said.

Morrissey was elected in January 2011. Under his watch, Arizona Republicans watched as they lost a majority of the state's nine congressional seats last month. In addition, the party also lost its super-majority at the state Capitol and failed elect a Republican mayor of Phoenix in 2009.

However, Republicans did win the state's first open U.S. Senate seat in nearly 20 years as Jeff Flake defeated Democrat Richard Carmona. The GOP also took all the seats on the little-watched Arizona Corporation Commission.